third_party/blink/renderer/platform/lifecycle_context_test.cc

/*
 * Copyright (C) 2013 Google Inc. All Rights Reserved.
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 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
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#include "testing/gtest/include/gtest/gtest.h"
#include "third_party/blink/renderer/platform/heap/handle.h"
#include "third_party/blink/renderer/platform/heap/persistent.h"
#include "third_party/blink/renderer/platform/lifecycle_notifier.h"
#include "third_party/blink/renderer/platform/lifecycle_observer.h"
#include "third_party/blink/renderer/platform/runtime_enabled_features.h"

namespace blink {

class TestingObserver;

class DummyContext final
    : public GarbageCollectedFinalized<DummyContext>,
      public LifecycleNotifier<DummyContext, TestingObserver> {
  USING_GARBAGE_COLLECTED_MIXIN(DummyContext);

 public:
  static DummyContext* Create() { return new DummyContext; }

  void Trace(blink::Visitor* visitor) override {
    LifecycleNotifier<DummyContext, TestingObserver>::Trace(visitor);
  }

  // Make the protected method public for testing.
  using LifecycleNotifier<DummyContext, TestingObserver>::ForEachObserver;
};

class TestingObserver final
    : public GarbageCollected<TestingObserver>,
      public LifecycleObserver<DummyContext, TestingObserver> {
  USING_GARBAGE_COLLECTED_MIXIN(TestingObserver);

 public:
  static TestingObserver* Create(DummyContext* context) {
    return new TestingObserver(context);
  }

  void ContextDestroyed(DummyContext* destroyed_context) {
    if (observer_to_remove_on_destruct_) {
      destroyed_context->RemoveObserver(observer_to_remove_on_destruct_);
      observer_to_remove_on_destruct_.Clear();
    }
    context_destroyed_called_ = true;
  }

  void Trace(blink::Visitor* visitor) override {
    visitor->Trace(observer_to_remove_on_destruct_);
    LifecycleObserver::Trace(visitor);
  }

  void Unobserve() { SetContext(nullptr); }

  void SetObserverToRemoveAndDestroy(
      TestingObserver* observer_to_remove_on_destruct) {
    DCHECK(!observer_to_remove_on_destruct_);
    observer_to_remove_on_destruct_ = observer_to_remove_on_destruct;
  }

  TestingObserver* InnerObserver() const {
    return observer_to_remove_on_destruct_;
  }
  bool ContextDestroyedCalled() const { return context_destroyed_called_; }

 private:
  explicit TestingObserver(DummyContext* context)
      : LifecycleObserver(context), context_destroyed_called_(false) {}

  Member<TestingObserver> observer_to_remove_on_destruct_;
  bool context_destroyed_called_;
};

TEST(LifecycleContextTest, ShouldObserveContextDestroyed) {
  DummyContext* context = DummyContext::Create();
  Persistent<TestingObserver> observer = TestingObserver::Create(context);

  EXPECT_EQ(observer->LifecycleContext(), context);
  EXPECT_FALSE(observer->ContextDestroyedCalled());
  context->NotifyContextDestroyed();
  context = nullptr;
  ThreadState::Current()->CollectAllGarbage();
  EXPECT_EQ(observer->LifecycleContext(), static_cast<DummyContext*>(nullptr));
  EXPECT_TRUE(observer->ContextDestroyedCalled());
}

TEST(LifecycleContextTest, ShouldNotObserveContextDestroyedIfUnobserve) {
  DummyContext* context = DummyContext::Create();
  Persistent<TestingObserver> observer = TestingObserver::Create(context);
  observer->Unobserve();
  context->NotifyContextDestroyed();
  context = nullptr;
  ThreadState::Current()->CollectAllGarbage();
  EXPECT_EQ(observer->LifecycleContext(), static_cast<DummyContext*>(nullptr));
  EXPECT_FALSE(observer->ContextDestroyedCalled());
}

TEST(LifecycleContextTest, ObserverRemovedDuringNotifyDestroyed) {
  DummyContext* context = DummyContext::Create();
  Persistent<TestingObserver> observer = TestingObserver::Create(context);
  TestingObserver* inner_observer = TestingObserver::Create(context);
  // Attach the observer to the other. When 'observer' is notified
  // of destruction, it will remove & destroy 'innerObserver'.
  observer->SetObserverToRemoveAndDestroy(inner_observer);

  EXPECT_EQ(observer->LifecycleContext(), context);
  EXPECT_EQ(observer->InnerObserver()->LifecycleContext(), context);
  EXPECT_FALSE(observer->ContextDestroyedCalled());
  EXPECT_FALSE(observer->InnerObserver()->ContextDestroyedCalled());

  context->NotifyContextDestroyed();
  EXPECT_EQ(observer->InnerObserver(), nullptr);
  context = nullptr;
  ThreadState::Current()->CollectAllGarbage();
  EXPECT_EQ(observer->LifecycleContext(), static_cast<DummyContext*>(nullptr));
  EXPECT_TRUE(observer->ContextDestroyedCalled());
}

// This is a regression test for http://crbug.com/854639.
TEST(LifecycleContextTest, ShouldNotHitCFICheckOnIncrementalMarking) {
  bool was_enabled = RuntimeEnabledFeatures::HeapIncrementalMarkingEnabled();
  RuntimeEnabledFeatures::SetHeapIncrementalMarkingEnabled(true);
  ThreadState* thread_state = ThreadState::Current();
  thread_state->IncrementalMarkingStart(BlinkGC::GCReason::kTesting);

  DummyContext* context = DummyContext::Create();

  // This should not cause a CFI check failure.
  Persistent<TestingObserver> observer = TestingObserver::Create(context);

  EXPECT_FALSE(observer->ContextDestroyedCalled());
  context->NotifyContextDestroyed();
  EXPECT_TRUE(observer->ContextDestroyedCalled());
  context = nullptr;

  while (thread_state->GetGCState() ==
         ThreadState::kIncrementalMarkingStepScheduled)
    thread_state->IncrementalMarkingStep();
  thread_state->IncrementalMarkingFinalize();

  RuntimeEnabledFeatures::SetHeapIncrementalMarkingEnabled(was_enabled);
}

TEST(LifecycleContextTest, ForEachObserver) {
  Persistent<DummyContext> context = DummyContext::Create();
  Persistent<TestingObserver> observer = TestingObserver::Create(context);

  HeapVector<Member<TestingObserver>> seen_observers;
  context->ForEachObserver(
      [&](TestingObserver* observer) { seen_observers.push_back(observer); });

  ASSERT_EQ(1u, seen_observers.size());
  EXPECT_EQ(observer.Get(), seen_observers[0].Get());

  seen_observers.clear();
  observer.Clear();
  ThreadState::Current()->CollectAllGarbage();

  context->ForEachObserver(
      [&](TestingObserver* observer) { seen_observers.push_back(observer); });
  ASSERT_EQ(0u, seen_observers.size());
}

}  // namespace blink